896 LIFE : OUTLINES OF GENERAL BIOLOGY 



LONG-PERSISTENT ANCIENT TYPES.— When Darwin made 

 his explorations in South America on his famous voyage of the 

 Beagle — that Columbus voyage in the course of which he discovered 

 a new, that is, an evolving, world — he was greatly impressed by the 

 fact that the living ant-eaters, whicVi are so characteristic of the 

 Neotropical region, had their counterparts in not less characteristic 

 fossil types. This correspondence, between the extinct and the 

 extant, was a seed in the fertile soil of Darwin's mind, and was one 

 of the facts that suggested to him the evolutionist point of view — 

 that the present is the child of the past. It is historically interesting 

 to quote Darwin's words: "This wonderful relationship in the same 

 continent between the dead and the living will, I do not doubt, 

 hereafter throw more light on the appearance of organic beings on 

 our earth, and their disappearance from it, than an}^ other class of 

 facts." Cautious, yet prophetic. 



Bagehot, who had an acute mind, once described the evolutionist 

 as one to whom everything is an antiquity. Instead of antiquity 

 we may read Tennyson's fine phrase, "the long result of time". 

 Organic Evolution is occasionally retrogressive, for its immediate 

 directive factor is the sifting of variations that fit, and the condi- 

 tions demanding fitness may spell degeneracy, as in parasitism; 

 but, on the whole, Organic Evolution is creative, integrative, and 

 progressive. It means testing all things and holding fast that which 

 is good. 



At the time of the Beagle voyage, Darwin did not know of 

 another South American type, the double-breathing mudfish, 

 Lepidosiren, which frequents the marshes of the Amazon and its 

 affluents, and lies low in its mud-burrow during the dry season. But 

 later on, in The Origin of Species, we find the great naturalist 

 using the now familiar title, "living fossils", and referring to 

 Lepidosiren as one of the persistent anomalous types which "connect 

 to a certain extent orders at present widely sundered in the natural 

 scale". For the sluggish Lepidosiren, which Graham Kerr has 

 studied to such good purpose, links modern fishes back to types of 

 Old Red Sandstone or even earlier origin, and points forwards in its 

 bmg-breathing to the Amphibians. Along with Ceratodus of Queens- 

 land and Protopterus of Africa, this quaint "Lolach", as the natives 

 caU it, is a modern survivor of an ancient race. It is a "living 

 fossil". 



Another modern fish that is hoary with antiquity is the Polypterus 

 of the Nile and other African rivers. Along with the agile Cala- 

 moichthys of Calabar, it represents to-day the great antique order 

 of Fringe-finned fishes or Crossopterygians, which began in the Old 

 Red Sandstone period or earlier, and gave rise to the Bony Fishes 

 and the Mudfishes, perhaps to Amphibians themselves. We are not 

 saying that there are fossil forms of Polypterus or its only surviving 



